Over the years, many implantable devices have been developed to monitor medical conditions and deliver therapy to a patient. Such devices included electrical stimulation devices for stimulating body organs and tissue to evoke a response for enhancing a body function or to control pain, and drug delivery devices for releasing a drug bolus at a selected site. Other more passive implantable and wearable medical devices have been developed for monitoring a patient's condition.
Chronically implanted cardiovascular devices for monitoring cardiovascular conditions and providing therapies for treating cardiac arrhythmias have vastly improved patients' quality of life as well as reduced mortality in patients susceptible to sudden death due to intractable, life threatening tachyarrhythmias.
Such implanted devices can also process the patient's electrogram and any measured physiological conditions employed in the diagnosis and store the data, for subsequent telemetry out on interrogation by the external programmer. In general, the manner of communicating between the transceivers of the external programmer and the implanted device during programming and interrogating is referred to as telemetry.
The short range of conventional device telemetry is itself viewed as unduly limiting the communication of information over a long distance. In the medical monitoring field, longer range, continuously accessible telemetry has been sought and systems for doing so have been proposed. In U.S. Pat. No. 5,113,869, Implantable Ambulatory Electrocardiogram Monitor to Nappholz, et al, for example, an implanted ambulatory ECG patient monitor is described that is provided with longer range telemetry communication with a variety of external accessory devices to telemeter out alarm signals and ECG data and to receive programming signals. The high frequency RF signals are encoded, including the implanted device serial number, to ensure that the communication is realized only with the proper implanted device and that it is not misprogrammed.
A remote, external programmer and analyzer as well as a remote telephonic communicator are also described that may be used in addition to, or alternately to, the personal communicator alarm and/or the full disclosure recorder. The programmer and analyzer may operate at a distance to the implanted AECG monitor to perform programming and interrogation functions. The implanted AECG may automatically transmit a beacon signal to the programmer and analyzer to initiate an interrogation function to transmit data to the programmer and analyzer on detection of an arrhythmia or a malfunction of the implanted AECG monitor detected in a self-diagnostic test. Or by setting a timer in the personal communicator alarm, the implanted AECG monitor may be automatically interrogated at preset times of day to telemeter out accumulated data to the telephonic communicator or the full disclosure recorder. The remote telephonic communicator may be part of the external programmer and analyzer and is automatically triggered by the alarm or data transmission from the implanted AECG monitor to establish a telephonic communication link and transmit the accumulated data or alarm and associated data to a previously designated clinic or physician's office through a modem.
A similar hand-held interrogator for an implanted pacemaker-cardioverter-defibrillator device is disclosed in U.S. Pat. No. 5,336,245, Storage Interrogation Apparatus for Cardiac Data, issued to Adams and Kroll in 1994, wherein the data accumulated in a limited capacity memory implanted device is telemetered out to a larger capacity, external data recorder. The accumulated data is also forwarded to a clinic employing an auto-dialer and FAX modem resident in a personal computer-based, programmer/interrogator.
U.S. Pat. No. 5,752,976, World wide patient location and data telemetry system for implantable medical devices, issued to Duffin, et al, in May 1998, referenced herein in its totality, is instructive for the present invention. This patent describes a system for communicating patient device information to and from a medical device implanted in an ambulatory patient and with a remote medical support network comprising: an implanted device telemetry transceiver within the implanted medical device for communicating data and operating instructions to and from the medical device in a coded communication, the implanted device telemetry transceiver having a transceiving range extending outside the patient's body a predetermined distance sufficient to receive and transmit coded telemetry communications at a distance from the patient's body; and an external patient communications control device adapted to be located in relation to the patient within the device transceiving range having a system controller for facilitating communications, an implant wireless interface including a control device telemetry transceiver for receiving and transmitting coded communications between the system controller and the implant device telemetry transceiver, a global positioning system coupled to said system controller for providing positioning data identifying the global position of the patient to the system controller; communications means for communicating with the remote medical support network; and communications network interface means coupled to the system controller and the communications means for selectively enabling the communications means for transmitting the positioning data to the medical support network and for selectively receiving commands from the medical support network. The medical support staff may initiate data/programming communications with the implanted medical device.
U.S. Pat. No. 5,891,180, Interrogation of an Implantable Medical Device Using Audible Sound Communication, to Greeninger et al, and U.S. Pat. No. 6,082,367, Audible Sound Communication from an Implantable Medical Device, to Greeninger and Thompson, both hereby incorporated by reference, are instructive on how data may be interrogated and telemetered out of the implanted device.
One of the issues unresolved by the '976 patent is the question of how to use this system to ensure that the implanting institution has an adequate inventory of implanted devices. If the information about inventory status at the implanting institution, such as the implantation of a medical device (a reduction in inventory) could be telemetered to the manufacturing site, the manufacturer could then build an identical device to replace the recently implanted device—a process called “build-to-order”.
Build-to-Order manufacturing and control systems are well known to those familiar with the art. Such systems were pioneered by Dell USA, when the company's founder, as far back as 1985, began to manufacture and assemble computers to meet the needs of the user customer. This method of manufacturing and delivery of the product has been further enhanced by allowing potential customers to specify the exact type of desktop or laptop computer s/he wishes to purchase. Overhead, in the form of an outlet store with its accompanying sales personnel and incremental costs, are non-existent. As a result, Dell USA is able to consistently provide quality products at consistently lower costs, as compared to its competition. Dell USA holds well over 200 patents, many of which relate directly to the design and implementation of its build-to-order process. To mention but two such patents, we may cite U.S. Pat. No. 5,894,571 Process for Configuring Software in a Build-to-Order Computer System, issued to O'Connor, and U.S. Pat. No. 5,995,757 Software Installation and Testing for a Build-to-Order Computer System, both hereby referenced in their totality.
Another model that may be cited comes from IBM that holds U.S. Pat. No. 6,078,900 in June, 2000, Method for Estimating Stock Levels in Production-Distribution Networks with Inventory Control, issued to Amberg et al., also referenced herein in its totality. That invention provides computer software for business management and a computer implemented method for estimating stock levels in production-distribution networks with inventory control.
There are many similarities between the computer industry and the medical device industry. Thus, it should be possible to adapt and improve upon these well-known build-to-order systems and methods to fit the needs of the medical device industry.
Medical device industries are growing at a rapid rate with a corresponding rapid growth and change in their production processes. At present, the distribution of these products requires multiple stockholding points. One of the great challenges in the medical device environment is a company's ability to meet end-customer demand for an adequate inventory to provide immediate availability for medical devices for which the need cannot be predicted in advance. Consuming (implanting) devices prior to the expiration of a device's shelf life and managing the transition to newly approved devices (e.g., by the FDA) pose additional challenges.
If inventories are managed successfully, rewards can be tremendous. However, the penalty for keeping too little stock or failure to replace stock in a hospital goes beyond the cost of foregone revenue for both the manufacturer and the hospital. It includes the potential for loss of life because the individual required medical device is not available. The penalty for keeping too much stock in inventory, on the other hand, includes the cost of financing a large inventory thereby reducing profit margins to those medical institutions. Further, the need to implant products before obsolecense and managing a smooth transition into new products pose various strategic and manufacturing challenges. Furthermore, consuming (implanting) devices prior to the expiration of a device's shelf life and managing the transition to newly approved devices (e.g., by the FDA) pose additional challenges.
The initial stocking of inventory, as currently practiced, involves the manufacturer's representative and a person at the institution who is intimately familiar with the usage of medical devices and the number of devices used by the medical institution, often the hospital administrator. Assuming the institution has purchased a certain number of devices, the representative ensures that the institution has a certain number of these devices on the “shelves.” The type of device and their number will reflect the nature and content of the contract governing the business relations, between the institution and the manufacturer and is usually based on expected, rather than actual, usage. Thus, there may be a distribution between basic, advanced, and more advanced technology, again conforming to the nature of the contract that governs the sale of such devices.
The manufacturer's representative maintains that initial inventory. If, however, and for one reason or another, the physician implanter has a greater number of patients who require the implantation of a medical device of one sort or another, the inventory of specific medical devices may become depleted. The situation often arises where the depletion of devices is not noticed until the physician requests a device to match the needs of the patient to be implanted the next day, or later in the day on which the request is made. What is to be done then? Usually a call is made to the manufacturer's local business office that may or may not have the exact model on hand. If so, someone has to bring it to the institution. This may involve many miles depending on the location of the business office relative to the medical institution. If this device is not available at the local business office, a call will be made to the manufacturer's central office or to the manufacturing facility. In such cases and even when Herculean efforts take place, the device will not usually arrive at the institution in time for the original scheduled implant. Often the implant must be postponed for several days. This is the primary issue that the present invention addresses.
A secondary issue that must be addressed occurs during those times when the device manufacturer is introducing a new product. The manufacturing facility must have on hand a rather large number of newer devices which the physicians and institutions will request for use upon approval for implant is received from an approving agency such as the FDA in the U.S.A. and other such agencies in Europe and Japan. Yet, until approval is given, none of the newer devices may be implanted. Only those that were previously approved may be implanted. If the approval is delayed for one reason or another, the manufacturer must maintain two inventories, one of the older and one of the newer product lines. In such cases, when approval is finally granted and because the physicians usually wish to make use of the newer technology, the manufacturer must usually retrieve the older product inventory and dispose of it in some way or other, usually at an economic loss to the manufacturer which, in turn, can bring about a subsequent increase in cost to the government, insurance payer, or patient.
The key challenge that the medical device industry must face is to determine where and in what quantities to hold safety stock in the network so as to protect against uncertainties, and to ensure that target customer service levels are met. Aggressive service requires significant inventory planning. Today, the determination of inventory levels is localized and often ad hoc, and not based on an analysis of optimal levels and deployment. As a result, the business impact, in terms of the trade-off between inventory investment and customer serviceability or delinquency, is far from optimal.
Determining the optimal inventory levels in individual medical institutions is extremely difficult, and few real-world inventory management systems have the capability to accurately predict target stock levels. The difficulty of the problem arises from the fact that the quantity of safety stock held at one stocking location, and the policy determining replenishment of inventory at that location, will affect other stockholding locations in the network. A system is needed that accurately represents the interdependencies of all links in a production-distribution network, and allows the manufacturer of medical devices to fill the institution's inventory on an automatic basis whenever that inventory is depleted by even one device as it is used.
Modern medical devices contain highly sophisticated hardware and software components that require specialized manufacturing processes. Further, these same devices require replacement on the shelves of a hospital on a timely basis when a unit in inventory is implanted in a patient. Hospitals, physicians, and other patient-care systems operate in a highly constrained economic environment. Inventory control is one way to reduce costs within these medical systems. Thus, a medical device manufacturing system that is interactive with and responsive to this environment is highly desirable. This is especially true if such a system can minimize the need for maintaining a large inventory of these medical devices, while sustaining the institution's ability to deliver efficient and effective medical care.
What is needed is a system that has the following goals: build products to refill the medical institution's inventory order, automatic replenishment of stock in days, and track manufacturing and product information in order to effectively service customers.